Anti-slip attachment for ladders

ABSTRACT

An anti-slip attachment for a ladder that forms a frictional engagement between the ladder and a metal gutter, so as to prevent the ladder from slipping laterally thereon. A layer of resiliently compressible material having a high surface coefficient of friction against smooth metal is mounted to the ladder so that it will bear against and be compressed by an edge of the gutter. The layer of resiliently compressible material may be at least one strip of resiliently compressible foam tape. The resiliently compressible material may be adhered directly to the side rails of the ladder so as to bear against the edge of a gutter when the ladder is rested thereon, or the layer or layers of resiliently compressible material may be mounted to a separate frame or bracket that is in turn mounted to the ladder itself. The anti-slip attachment helps to reduce the likelihood of fall injuries due to the ladder slipping sideways along a metal gutter during use.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 60/524,134 filed on Nov. 20, 2003.

BACKGROUND

a. Field of the Invention

The present invention relates generally to safety devices for ladders,and, more particularly, to an attachment for preventing ladder fromslipping laterally against a gutter during use.

b. Background

Ladders in general, and extension ladders in particular, presentsignificant safety concerns. It is well documented that falls fromladders result in numerous injuries and deaths on an annual basis.

One particular hazard is the tendency of ladders to slip sideways whenresting against gutters. As can been seen in FIG. 1, a person 10 whencleaning or repairing a gutter 12 tends to reach out to one side or theother when working, due to the inconvenience involving in descending andmoving the ladder 14 to another location, with the result that thisunbalances the ladder and tends to cause it to slide laterally on thegutter and possibly topple over. Even more dangerous is the tendency ofthe ladder to slip when attempting to step onto it from the roof inorder to descend, when the user is facing backwards and feeling for arung with his foot.

The frequency of this hazard is increasing due to the increasing use ofaluminum (and other metal and slippery-surfaced materials) in theconstruction of both gutters and ladders. For example, when an aluminumextension ladder is placed against an aluminum gutter there is almost nofrictional resistance to the ladder sliding laterally.

As a partial solution, some ladders have been fitted with various formsof stabilizing struts and braces which rest against the ground. Theseare at best only a partial solution, and become less effective as theladder is extended to increased heights. Moreover, the struts and bracesare cumbersome and make the ladder to difficult to store or transport,and also add significant cost.

Accordingly, there exists a need for an attachment for effectivelypreventing a ladder from slipping laterally when placed against a gutteror similar structure or surface. Furthermore, there exists a need forsuch an attachment that is effective regardless of the height to whichthe ladder is extended. Still further, there exists a need for such anattachment that does not encumber the transportation or storage of theladder, or otherwise compromise its use. Still further, there exists aneed for such an attachment that can be used with a wide variety ofconventional ladders, both new and those already in use, withoutrequiring significant modification thereof. Still further, there existsa need for such an attachment that is inexpensive and yet durable andlong lasting in use.

SUMMARY OF THE INVENTION

The present invention has solved the problems cited above, and is ananti-slip attachment for a ladder that forms a frictional engagementbetween the ladder and the metal gutter or similar structure when theladder is placed thereon.

Broadly, the invention comprises (a) a layer of resiliently compressiblematerial having a comparatively high surface coefficiency of frictionagainst smooth metal, and (b) means for mounting the layer ofresiliently compressible material to a ladder so that the layer willbear against and be partially compressed by the edge of the gutter whenthe ladder is rested thereon.

The layer of resiliently compressible material may comprise a strip ofthe resiliently compressible material, and the means for mounting thematerial to the ladder may comprise an adhesive for being adhered to theforward faces of the side rails of the ladder. The strip may comprise aroll of the resiliently compressible material having an adhesivebacking.

Alternatively, the means for mounting the layer of resilientlycompressible material to the ladder may comprise a frame having theresiliently compressible material mounted to a face thereof, and meansfor mounting the frame to the ladder. The frame may comprise first andsecond clips that are mountable to the side rails of the ladder so thatthe faces having the layer of resiliently compressible material aredirected towards the gutter when the ladder is placed thereon.

The resiliently compressible material may comprise a resilientlycompressible foam material. The resiliently compressible foam materialmay be a PVC foam material.

The layer of resiliently compressible material may be configured so thatthe material will be only partially compressed when forced against thegutter under a predetermined maximum operating load of the ladder, sothat the layer of resiliently compressible material will retain areserve range of compression when the ladder is fully loaded. Thereserve range of compression may be about 50% of the total range ofcompression of the layer of material.

The present invention also provides an anti-slip ladder assembly,comprising (a) a ladder, and (b) a layer of resiliently compressiblematerial having a comparatively high surface coefficient of frictionthat is mounted to the ladder so as to bear against and engage an edgeof a gutter when the ladder is placed thereon. The layer of resilientlycompressible material may comprise first and second strips ofresiliently compressible material that are adhered to the faces of firstand second side rails of the ladder. The resiliently compressiblematerial may comprise strips of resiliently compressible foam materialhaving an adhesive backing. The resiliently compressible material maycomprise resiliently compressible PVC foam material. The layer ofresiliently compressible material may be configured so that the materialwill be only partially compressed when forced against the gutter under apredetermined maximum operating load of the ladder, so that the layer ofresiliently compressible material will retain a reserve range ofcompression when the ladder is fully loaded. The reserve range ofcompression may be about 50% of the total range of compression of thelayer of material.

The invention further provides a method for forming a frictionalengagement between a ladder and a metal gutter, comprising the steps ofmounting to a ladder a layer of resiliently compressible material havinga high surface coefficient of friction against smooth metal, and restingthe ladder against a metal gutter so that the layer of resilientlycompressible material establishes a frictional engagement that preventsthe ladder from slipping laterally along the edge of the gutter.

These and other features and advantages of the present invention will beapparent from a reading of the following detailed description withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational, environmental view of a ladder in accordancewith the prior art, showing the manner in which this tends to slip alongthe gutter as the operator reaches to one side;

FIG. 2 is an elevational view of a ladder having an anti-slip attachmentin accordance with the present invention adhered thereto, showing themanner in which the attachment engages the metal gutter of a house whenplaced thereon;

FIG. 3 is an enlarged, cross-sectional view of the area of contactbetween the ladder of FIG. 2 and the gutter against which it is placed,showing the manner in which the compressible layer of the anti-slipattachment yields resiliently to conform to and engage the surface ofthe gutter;

FIG. 4 is an elevational, partial view of a ladder having a strip ofcompressible material being applied thereto from a roll of the material,so as to form the anti-slip attachment of FIGS. 2-3;

FIG. 5 is an elevational view, similar to FIG. 2, showing an anti-slipattachment in accordance with a second embodiment of the presentinvention, in which the yieldingly compressible material is mounted to apair of clips that are fitted over the side rails of the ladder, theladder being shown in a cross-section taken along line 5-5 in FIG. 6;

FIG. 6 is an elevational view of the ladder and anti-slip attachments ofFIG. 5, showing the position of the clips on the side rails of theladder; and

FIG. 7 is a cross-sectional view of the ladder and anti-slip attachmentsof FIGS. 5-6, taken along line 7-7 in FIG. 6, showing the manner inwhich the clips fit over and engage the side rails of the ladder;

FIG. 8 is an elevational view, similar to FIG. 5, showing an anti-slipattachment in accordance with a third embodiment of the presentinvention, in which the yieldingly compressible material is mounted to apair of channel-shaped frames that are slipped over the side rails ofthe ladder;

FIG. 9 is a perspective view of one of the slip-on, channel-shapedframes of FIG. 8, showing the configuration of the frame and the stripof resiliently compressible material thereon in greater detail;

FIG. 10 is a first partial, elevational view of the ladder and one ofthe slip-on frames of FIGS. 8-9, showing the manner in which the upperend of a side rail enters and is received in the channel-shaped frame asthe latter is slid onto the rail;

FIG. 11 is a second partial, elevational view of the side rail andslip-on frame of FIG. 10, showing the manner in which the side rail fitswithin and is engaged by the channel-shaped frame as the frame is slidonto the rail and into the desired position;

FIG. 12 is a cross-sectional view, taken along line 12-12 in FIG. 11,showing the relationship of the channel-shaped frame and strip ofresiliently compressible material to the side rail of the ladder ingreater detail; and

FIG. 13 is a cross-sectional view of an anti-slip attachment assembly inaccordance with a fourth embodiment of the present invention, showingthe manner in which the brackets thereof are mounted by a threaded rodwhich passes through one of the staves of the ladder.

DETAILED DESCRIPTION

The present invention is an anti-slip attachment for a ladder whichfrictionally engages the surface of a metal gutter or similar surfacestructure so as to prevent the ladder from sliding thereon. FIGS. 2-7illustrate two embodiments of the invention.

In the first preferred embodiment that is illustrated in FIG. 2, theattachment is formed of a strip of resiliently compressible material 20that is adhered to the forward face 22 of each rail 24 of the ladder 26.The surface of the resiliently compressible layer 20 will consequentlybear against the lip 28 of the gutter 30 when the ladder is placedthereon, as shown in FIG. 2.

The pressure of the ladder against the gutter causes the lip 28 of thegutter to press into the resilient material of the anti-slip attachment,as shown in FIG. 3. This causes the resiliently compressible material todeform so that its surface follows the contour of the gutter lip,forming a contact patch 32 having an increased surface area. Thecompressible material is selected to have surface qualities similar tothat of soft rubber, i.e., it has a high degree of “tackiness” andresistance to slipping when pressed against a smooth metal surface. Thematerial thus has a high surface coefficient of friction, e.g., a staticcoefficient of friction (μ_(s)) well above 0.5 and preferably aboveabout 0.9.

The large contact patches 32 consequently establish a firm frictionalengagement with the lip of the gutter that prevents the ladder fromsliding laterally thereon. Moreover, any tipping movement will cause therail of the ladder on the side towards the direction of tipping to slidedownwardly (as well as laterally) against the gutter (see FIG. 1); asthis happens, the material of the compressible strip in the area 34 justabove the contact patch (see FIG. 3) will tend to build or “mound” up soas to abut the upper surface 36 of the gutter lip, further acting toarrest the movement of the ladder.

In combination, these actions of the resiliently compressible strips(i.e., the frictional engagement of the contact patch in combinationwith the abutment of the material against the upper surface of thegutter lip) are extremely effective in preventing the ladder fromdeveloping any tipping or sliding motion during use; in prototypetesting, using anti-slip strips in accordance with the preferredembodiment of the present invention, it has been found essentiallyimpossible for a person to cause the ladder to slide laterally againstan aluminum gutter, even when pulling forcefully in a sideways directionon the gutter itself.

Another particular advantage of the elongate configuration of the stripsof resiliently compressible material is that this makes it very easy forthe operator to position the anti-slip material against the edge of thegutter, regardless of differences in the height of the gutter above theground. As is well know, the height of most extension ladders isadjustable only in increments (typically, by the distance between theindividual staves of the ladder); the vertical length of the elongatestrips avoids the problem of the anti-slip areas being positioned aboveor below the gutter when the ladder is adjusted to the nearestincremental height. The elongate dimension of the strips also preventsthem from moving off of and losing contact with the edge of the gutterin the event that some movement occurs that changes the angle of theladder relative to the gutter. For most conventional extension ladders,it is preferred that the length of the strips be at least as great asthe spacing between the staves/rungs (e.g., about 10-16 inches),although much longer strips (e.g., 3-5 feet or more) may be advantageousfrom the standpoint of convenience. Moreover, it will be understood thatin some embodiments the resiliently compressible, anti-slip material maybe provided in other shapes besides elongate, rectangular strips, forexample, in an oval or rounded configuration.

In order for the anti-slip strips to provide the above advantages, it isimportant that the resiliently compressible material be selected to havea durometer, or indentation hardness, in combination with its thicknesssuch that it will significantly compress but will not “bottom out”against the ladder rails 22 under normal loads. In other words, thematerial is preferably selected so that, when the ladder with which itis used is at its maximum normally acceptable inclination and workingload, with the rails of the ladder pressing against the edge of thegutter, the material will not be completely collapsed and will retain adegree of compressible travel. Thus, as is shown in FIG. 3, even whenthe ladder is bearing the full load of a user and associated tools,etc., the material of the strips 20 has not bottomed out, and an area 38of reserve compression remains available between the gutter lip and theforward faces 22 of the ladder rails. The amount of reserve compressionmay vary depending on design factors, however, it is generally suitablethat the material be selected to yield by about 50% of its totalavailable compression when subjected to a maximum operating load of theladder within a specified range of lean angles.

As can be seen with further reference to FIG. 3, each of the strips 20of the anti-slip attachment of the preferred embodiment is formed by alayer of resiliently compressible foam material 40 backed by a layer ofadhesive 42 that affixes the compressible material to the face 22 of therail. FIG. 4, in turn, illustrates a method in which the anti-slipmaterial is conveniently supplied in the form of a roll 34 of adhesivecushioning tape. This can be packaged and supplied to the purchaser,separately from or together with the ladder as desired, and is easilyapplied to the faces of the rails 24 by simply unrolling the tape in aconventional fashion and pressing it against the surface 22 so that thematerial adheres firmly thereto. It will be understood, however, thatother forms of application may be employed, for example, the resilientlycompressible material may be extruded or molded directly on the faces ofthe ladder rails in an OEM operation, or may be formed as an integralpart of the faces of the rails themselves.

Suitable adhesive foam tape material is available from Saint-GobainPerformance Plastics, Granville, N.Y., with equivalent products beingavailable from other manufacturers. Cellular PVC (polyvinyl chloride)foam material is generally preferred due to its comparatively highsurface coefficient of friction and its ability to establish firmfrictional engagement under both wet and dry conditions, plus itsoverall durability and resistance to abrasion; it will be understood,however, that other resilient materials may be used, such as urethane,polyurethane, silicone or rubber foams or various non-cellularrubber-like materials, for example. Using firm PVC foam material inreadily available durometers, suitable dimensions for the adhesive tapeare 1⅛ inches wide by ⅜ inch thick, which again may vary depending ondesign factors.

One example of an eminently suitable high-density, closed-cell PVC foammaterial, available from Saint-Gobain Performance Plastics, has theproperties set forth in the following Table A: TABLE A Properties TestMethod Value Thickness, inches (mm) .375 (8.5) Hardness Shore OO 52Density lbs./ft³ (kg/m³) ASTM D1667   15 (240) Compression ForceDeflection psi ASTM D1667   9 (64) (kPa) @ 30% Force to Compress, psi(kPA) @ ASTM D1667   14 (94) 30%

In the second embodiment, which is illustrated in FIGS. 5-7, there arefirst and second clips, 50 a, 50 b that attach to the two rails 52 a, 52b of the ladder and which engage the lip 28 of the gutter 30 insubstantially the same manner as described above. The clips consequentlyprovide separate frames on which the tape is mounted, which are in turnmountable to the ladder.

As can be seen in FIG. 7, each of the clips is formed in the shape ofsemi-enclosed channel. In the illustrated embodiment the channel isconstructed of steel-sheet metal, however, it will be understood thatplastic or other suitable materials may be used. The channel includes acomparatively wide web 54 having a flange 56 along its forward edge, thestrip of foam material 58 being adhered to the outer surface thereof. Asecond flange 58 along the opposite edge of the web 54 is bent backparallel to the web so as to form a return 60 that defines semi enclosedU-shaped channel area 26. The inside angle between the web and theforward flange 56 is somewhat less than 90°, e.g., 80-85°.

To install one of the clips on a rail of the ladder, the U-shapedchannel area 60 is first slipped over the rearward flange 64 of theladder rail and the clip is then pulled/pushed forwardly. When therearward flange of the ladder is fully seated against the rearwardflange 58 of the clip, as is shown in FIG. 7, the forward flange 56 isbent forwardly to widen the spacing between the forward and rearwardflanges of the clip sufficiently that the former can be slipped over theforward flange 66 of the ladder rail. When the clip has been pressedhome, so that its web lies generally parallel to the web 68 of theladder rail, the forward flange 56 snaps resiliently back to its initialorientation to lock the clip in place. The strip of resilientlycompressible anti-slip material is thus positioned so that it will becompressed between the gutter and the rail of the ladder during use.

In a third embodiment, which is illustrated in FIGS. 8-12, there are twochannel-shaped frames 70 a, 70 b (only 70 a being visible in FIG. 8),that have a channel-shaped configuration and that slip over the two siderails 72 a, 72 b of the ladder rather than clipping onto them in themanner shown in FIGS. 5-7.

As can be seen in FIG. 9, each of the slip-on frames has a generallychannel-shaped configuration, with a side web 74 and forward andrearward flanges 76, 78 with returns 80, 82, that in combination definea semi-enclosed, U-shaped channel area 84; the generally U-shapedconfiguration facilitates manufacture of the frames from stamped/bentsheet metal, however, it will be understood that in some embodimentsthat the channel areas may be fully enclosed. A strip 86 of theresiliently compressible material is mounted to the forwardly-directedface of each forward flange 76, in a manner similar to the embodimentdescribed with regard to FIGS. 5-7. However, at the upper and lower endsof the rearward flange 78 a pair of ramp-shaped biasing members 88 a, 88b protrude inwardly towards the channel area 84. In the embodiment thatis illustrated, the biasing members are formed of separate pieces ofresiliently flexible material (e.g., metal or plastic), each having amounting portion 90 that is spot welded, bonded or otherwise mounted tothe inside surface 92 of the rearward flange 78 (see FIG. 10), with aleaf portion 94 that bends forwardly from the mounting portion so as toextend into the channel area. This provides the advantage of being ableto form the biasing members of a material having superior resiliency andwear characteristics as compared with the material of the frame;however, it will be understood that in some embodiments the biasingmembers may be formed integrally (e.g., stamped or molded) with and ofthe same material as the frame itself.

As can be seen in FIG. 10, the side web 74 and therefore the channelarea 84 is sized somewhat wider than the side rail of the ladder. Theleaf portions 94 of the biasing members 88 a, 88 b include main rampportions 96 that extend into the channel area to define a width that inturn is less than that of the side rails; distal ramp portions 98 at theends of the main ramp portions are angled back outwardly towards therearward side of the frame.

Accordingly, as can be seen in FIG. 10, the frame members 70 a, 70 b canbe slid onto the upper ends of the side rails 72 a, 72 b, in thedirection indicated by arrow 100. As this is done, the distal rampportion 98 contacts and rides over the upper, rearward corner of theside rail (which is typically radiussed as shown), so that the leafportion of the biasing member is forced outwardly in the directionindicated by arrow 104. As a result, the leaf portion develops an inwardbias against the rearward surface 106 of the rail as the frame is slidthereover.

As a result, the upper and lower biasing members 88 a, 88 b maintain aconstant inward pressure towards rails, as indicated by arrow 110 inFIG. 11. This generates a sliding but comparatively high-frictionengagement at the contact areas between the rearward surfaces 106 of therails and the junctures/apexes 108 of the ramp portions of the biasingmembers. The frictional engagement is sufficiently high to hold theframes in place, but low enough to be overcome by simply grasping theframes and pushing them in one direction or the other. Consequently, theoperator is able to conveniently slide the frames to the desiredlocation along the rails, at which the strips of resilientlycompressible material will contact the gutter, after which thefrictional engagement will maintain the frames in position and preventthem from sliding until the operator next desires to adjust theirpositions. Furthermore, as can be seen in FIG. 12, the forward pressureexerted by the biasing members holds the forward flange of the framefirmly in place against the front surface 112 of the rail, so as to forma stable interfit in which the anti-slip strips 86 are properlypositioned at the front edges of the ladder.

FIG. 13 shows a fourth embodiment of the invention, in which the frames120 a, 120 b have a somewhat simplified configuration, with the forwardand rearward flanges 122, 124 extending at right angles to the webs 126.As with the embodiments described above, the strips of resilientlycompressible cushioning material 128 are adhered to the outer surfacesof the forward flanges 122. In this embodiment, however, mounting isaccomplished by means of a threaded rod 130 that passes through a hollowinterior of one of the staves 132 of the ladder; conventionally, thestaves of aluminum ladders are hollow and open at each end so that therod can be readily passed therethrough. First and second wing nuts 134are mounted on the ends of the rod 130 and secure the clips to the railsof the ladder when tightened; suitably, the rod is a 20-inch length of¼-inch ready rod, with ¼-inch wing nuts on each end. However, it will beunderstood that in some embodiments a nut may be used on only one end ofthe rod, with the other end being a bolt head or fixed to the oppositeclip; moreover, other attachment and tightening means may be used inother embodiments.

The embodiments which are shown in FIGS. 5-13 illustrate just a few ofmany different structures that may be used to provide an anti-slipattachment in which the resiliently compressible material mounts to theladder via a secondary structure or frame rather than being adhereddirectly to the ladder rails themselves. As a general rule, thoseembodiments which employ secondary structures that are faced with thenon-slip compressible material may be somewhat more costly than thefirst embodiment described above (i.e., in which the compressible tapeis adhered directly to the faces of the rails), however, they may offercertain advantages in terms of being able to provide contact patchesthat are wider (and therefore “grippier”) than those which are limitedto the width of the individual rails of the ladder. It will beunderstood, however, that all such embodiments fall within the scope andspirit of the present invention, regardless of the whether theresiliently compressible material is mounted directly on the rails ofthe ladder or on a secondary frame or structure that in turn mounts tothe rails and/or staves of the ladder.

It is to be recognized that various alterations, modifications, and/oradditions may be introduced into the constructions and arrangements ofparts described above without departing from the spirit or ambit of thepresent invention.

1. An anti-slip attachment for a ladder that forms a frictionalengagement between said ladder and a metal gutter, said anti-slipattachment comprising: a layer of resiliently compressible materialhaving a high surface coefficient of friction against smooth metal; andmeans for mounting said layer of resiliently compressible material to aladder so that said layer will bear against and be compressed by an edgeof a metal gutter when said ladder is rested thereon; whereby said layerof resiliently compressible material establishes a frictional engagementthat prevents said ladder from slipping laterally along said edge ofsaid gutter.
 2. The anti-slip attachment of claim 1, wherein said layerof resiliently compressible material comprises: at least one elongatestrip of said resiliently compressible material.
 3. The anti-slipattachment of claim 2, wherein said means for mounting said layer ofresiliently compressible material to a ladder comprises: a layer ofadhesive on said strip of resiliently compressible material for adheringsaid strip to a face of at least one elongate side rail of a ladder. 4.The anti-slip attachment of claim 3, wherein said strip of resilientlycompressible material comprises: a roll of resiliently compressible tapehaving said layer adhesive formed thereon.
 5. The anti-slip attachmentof claim 1, wherein said means for mounting said layer of resilientlycompressible material to a ladder comprises: a frame having said layerof resiliently compressible material mounted to a face thereof; andmeans for mounting said frame to a ladder so that said face of saidframe bears against a gutter when said ladder is rested thereon.
 6. Theanti-slip attachment of claim 5, wherein said frame comprises: first andsecond clip members that are attachable to first and second side railsof a ladder so that said layers of resiliently compressible material arepositioned between said side rails and a gutter when said ladder isrested thereon.
 7. The anti-slip attachment of claim 5, wherein saidframe comprises: first and second bracket members for fitting over firstand second side rails of a ladder so that said layers of resilientlycompressible material are positioned between said side rails and agutter when said ladder is rested thereon; and a tie rod for passingthrough a stave of said ladder so as to join said brackets and securesaid bracket members on said side rails of said ladder.
 8. The anti-slipattachment of claim 1, wherein said layer of resiliently compressiblematerial comprises: a layer of resiliently compressible foam material.9. The anti-slip attachment of claim 8, wherein said resilientlycompressible foam material comprises: resiliently compressible PVC foammaterial.
 10. The anti-slip attachment of claim 1, wherein said layer ofresiliently compressible material comprises: a layer of resilientlycompressible material having a durometer selected so that said layerwill be only partially compressed when pressed against an edge of agutter by a ladder at a predetermined angle and maximum load, so thatsaid layer will retain a reserve range of compression when said ladderis fully loaded.
 11. The anti-slip attachment of claim 10, wherein saiddurometer is selected so that said layer will be compressed only about50 percent when pressed against an edge of a gutter by a ladder at saidpredetermined angle and maximum load, so that said layer will retain areserve range of compression of about 50 percent when said ladder isfully loaded.
 12. An anti-slip ladder assembly that forms a frictionalengagement with a metal gutter, said ladder assembly comprising: aladder; and a layer of resiliently compressible material having a highsurface coefficient of friction against smooth metal, said layer ofcompressible material being mounted to said ladder so that said layerwill bear against and be compressed by an edge of a metal gutter whensaid ladder is rested thereon; whereby said layer of resilientlycompressible material establishes a frictional engagement that preventssaid ladder from slipping laterally along said edge of said gutter. 13.The anti-slip ladder assembly of claim 12, wherein said layer ofresiliently compressible material comprises: an elongate strip ofresiliently compressible material that is mounted to a face of at leastone elongate side rail of said ladder.
 14. The anti-slip ladder assemblyof claim 12, wherein said layer of resiliently compressible materialcomprises: first and second elongate strips of resiliently compressiblematerial adhered to faces of first and second side rails of said ladder.15. The anti-slip ladder assembly of claim 12, wherein said assemblyfurther comprises: a frame having said layer of resiliently compressiblematerial mounted to a face thereof; and means for mounting said frame toa said ladder so that a said face of said frame bears against a gutterwhen said ladder is rested thereon.
 16. The anti-slip ladder assembly ofclaim 15, wherein said frame comprises: first and second clip membersthat are attachable to first and second side rails of a ladder so thatsaid layers of resiliently compressible material are positioned betweensaid side rails and a gutter when said ladder is rested thereon.
 17. Theanti-slip ladder assembly of claim 15, wherein said frame comprises:first and second bracket members for fitting over first and second siderails of a ladder so that said layers of resiliently compressiblematerial are positioned between said side rails and a gutter when saidladder is rested thereon; and a tie rod for passing through a hollowstave of said ladder so as to join said brackets and secure said bracketmembers on said side rails of said ladder.
 18. The anti-slip ladderassembly of claim 12, wherein said layer of resiliently compressiblematerial comprises: a layer of resiliently compressible foam material.19. The anti-slip ladder assembly of claim 18, wherein said resilientlycompressible foam material comprises: resiliently compressible PVC foammaterial.
 20. The anti-slip ladder assembly of claim 12, wherein saidlayer of resiliently compressible material comprises: a layer ofresiliently compressible material having a durometer selected so thatsaid layer will be only partially compressed when pressed against anedge of a gutter by a ladder at a predetermined angle and maximum load,so that said layer will retain a reserve range of compression when saidladder is fully loaded.
 21. The anti-slip ladder assembly of claim 20,wherein said durometer is selected so that said layer will be compressedonly about 50 percent when pressed against an edge of a gutter by aladder at said predetermined angle and maximum load, so that said layerwill retain a reserve range of compression of about 50 percent when saidladder is fully loaded.
 22. A method for forming a frictional engagementbetween a ladder and a metal gutter, said method comprising the stepsof: mounting to a ladder a layer of resiliently compressible materialhaving a high surface coefficient of friction against smooth metal; andresting said ladder against a metal gutter so that said layer ofresiliently compressible material bears against and is compressed by anedge of said metal gutter; whereby said layer of resilientlycompressible material establishes a frictional engagement that preventssaid ladder from slipping laterally along said edge of said gutter. 23.The method of claim 22, wherein the step of mounting said layer ofresiliently compressible material to a ladder comprises: mounting anelongate strip of said resiliently compressible material to a face of atleast one elongate side rail of said ladder.
 24. The method of claim 23,wherein the step of mounting an elongate strip of said resilientlycompressible material to at least one side rail of said ladder comprisesadhering first and second strips of said resiliently compressiblematerial to first and second side rails of said ladder.
 25. The methodof claim 22, wherein the step of mounting said layer of resilientlycompressible material to a ladder comprises: mounting said layer ofresiliently compressible material to a face of a frame; and mountingsaid frame to said ladder so that said face of said frame bears againsta gutter when said ladder is rested thereon.
 26. The method of claim 22,wherein the step of mounting a layer of resiliently compressiblematerial to a ladder comprises: mounting to said ladder a layer ofresiliently compressible foam material.
 27. The method of claim 26,wherein said resiliently compressible foam material is a PVC foammaterial.
 28. The method of claim 22, further comprising the step of:selecting said layer of resiliently compressible material to have adurometer such that said layer will be only partially compressed whenpressed against an edge of a gutter by said ladder at a predeterminedangle and maximum load, so that said layer will retain a reserve rangeof compression when said ladder is fully loaded.